Now the noise

[Matty_V]

So my amp is sounding pretty awesome now that the PI issue is resolved. But there is lots of hum. I rewired the grounding scheme like on merlins site, and used individual filter caps instead of a cap can but its still just as noisy as before. I notice it gets louder/quieter depending on what direction my guitar is facing. I have an older house with crappy wiring, and using one of those 3-prong adapters on the wall outlet, then into my surge protector.

Ideas? Wisdom? Axioms?

[Willabe]

Matty_V does your guitar have single coil pup's? They do that with their proximity to the amp.

That's not safe to use that 3 prong ground lifter, get rid of it.   


       Brad     

 

[jojokeo]

I was thinking same w/ single coils however unplug chord from guitar - noise same, better, or worse? If it goes down then it's standard single coil issues. Noise floor gets worse the higher the gain, power level, and treble/presence settings - all standard fair. The usual questions are lead dress, grounding, elevated heaters, etc.? Amp power chord grounding shouldn't cause this to be worse, didn't w/ Fender amps back in the day.

[HotBluePlates]

Your guitar is likely picking up the hum. The fact that it changes depending on the direction you face the guitar supports this. In fact, if you had single coils too close to the amp's PT, you can pick up hum from the PT, which is then amplified by the amp.

Unplug your guitar to evaluate the hum/noise level. ASSuming the input jacks short the tip to ground (as is standard with all old Fender amps, most others too), and you have this wired correctly, you should only be hearing the noise the amp is making. If you miswire the input jacks, the hot lead of the jack will pick up all sorts of noise out of the air, and allow the amp to amplify it (when nothing is plugged in the amp).

[Matty_V]

Yeah I was using the tele, I'll plug in the humbucker after work and take a listen. I'm not sure how I can not use an adapter. My wall is 2 prong, my amp is 3 prong. No way am I fiddling with the outlets on a house I'm renting. I'll also try yanking the patch cord to hear if that kills the noise. I want to say that it doesn't, but its been a little while. Heaters are elevated. I'll check the input jack too.

[phsyconoodler]

Quote:"My wall is 2 prong, my amp is 3 prong."

  Ok,you answered most of your own question here.You need to be able to reverse the wall socket to see if that helps.With a two prong no ground AC source all bets are off.
  I have no ground in my house and I get noise until I touch my guitars strings.No ground.
It's going to be pretty noisy no matter what you do.
  But mine aren't particularly noisy,just a bit when I'm not touching the strings,so maybe you don't have the filaments wired right or you forgot to ground the center tap of use a couple of 100 ohm virtual resistors??

[stingray_65]

Hey Matty,

If you're using one of those old adapters (Grounded 3 prong - 2 prong) make sure you connect the little ground connector to the wall plate screw.

After that, use your meter, set to 200VAC, and check between the big slot on the 3 prong to the cover screw, then the little slot. with luck, you'll have 0V big slot and 120V small slot. If so you have some sort of earth ground.

My old place had lath and plaster and some sort of chicken wire to hold the plaster. the chicken wire was touching the metal outlet box and plumbing in the kitchen and living room outlets. The bedrooms weren't so lucky.

So maybe also try different outlets in your house, you may get lucky and find one.

OH! check your bathroom! the outlets should have been converted to GFCI and they will have grounds.

Ray

[Matty_V]

Oooh lots of stuff to play with when I get home.

Electronics is not my first language. So, except for a 3rd ground prong, how does 2 prong differ from 3 prong?

[Shrapnel]

Oooh lots of stuff to play with when I get home.

Electronics is not my first language. So, except for a 3rd ground prong, how does 2 prong differ from 3 prong?

Two prong and three prong are supposed to be the same other than the ground "safety" connection.

Hot (black wire normally, small slot) is the AC supply, "neutral" or "common" (white wire normally, wide slot) AC return (to ground). Ground (round, pin) slot and wire it with a green wire for safety ground.

What's the difference between Ground and Neutral then? Not much really other than use. Neutral is specifically for the return loop of the AC circuit and the Ground is for safety only. Correctly wired, Ground and neutral will only ever connect at one point: The service entrance (where the power actually comes in as 120-0-120).

NOTE: Dependent on who wired the house, Neutral and Hot could be reversed as far as what is on what slot in the socket. Meaning: Don't count on the neutral as always being on the wide slot. I know our resident electricians here are pretty good about getting it right though.  Sometimes black and white are reversed on both ends too (with the result being neutral on wide, hot on narrow)

[Matty_V]

10-4. Thanks a bunch, makes total sense.

[jojokeo]

This may help someone w/ their house? But I had to re-do all of my recepticle outlets in my house after I first bought it. The wiring was all dropped from above and it actually did have ground wiring ran inside the walls but the grounds were all cut at the boxes! I simply cut a new box in above all of the old ones and re-pulled the grounds into the new boxes, installed new recepticles w/ three prong outlets and I was back in business after getting a drywall guy to repair all of the holes in the drywall I had made. Another note was that I also re-copper piped the house, put in all new sewer lines, installed ceiling fan boxes, bull-nosed all wall corners, and a bunch of other "fun" stuff so I had a lot of drywall to repair and replace in one large job at the end. But at the end of the day, it was all worth it by far.

[Matty_V]

My landlord might not approve of that, as much as I want to. I'm not a fan of half-assery but I'll just have to deal with it for now. I probed the outlet I've been using and I get 0v at the neutral and 117v at the hot measuring from the adapter ground prong, so they aren't reversed. Onto the other options...

[stingray_65]

My landlord might not approve of that, as much as I want to. I'm not a fan of half-assery but I'll just have to deal with it for now. I probed the outlet I've been using and I get 0v at the neutral and 117v at the hot measuring from the adapter ground prong, so they aren't reversed. Onto the other options...

AH!
not only are they not reversed, but you have a earth ground! (at the screw)

[Madison]

Just get a copper spike and stick it a foot or two down in the Earth (IOW ground)
Run a wire off that, through a window, to the 3rd prong of power strip inside.
Problems solved.
Heck,you could  probably get away with a piece of rebar in the ground.

To check it before attaching it to the strip, get the ground/Earth wire inside and touch it to a bare part of the chassis.
I bet your amp will shut up.

Make sure your guitar is shielded correctly.
Crappy pickups can be a problem too.

Get the ground/3 prong situation solved on the amp first!

[Matty_V]

Thats a pretty sweet idea! I'll look for some "cleverly" placed rebar in my man cave. I used a better patch cord and my humbucker hollow body and the hum was gone, more of a hisssssssss now. And it gets a little fuzzy when I take my hands off the strings like psycho mentioned.

This thing is wild, 3/4 volume and hello oscillation. Going to attach some grid stoppers and other housekeeping items.

[Merlin]

Another little test for you: put a non-stainless-steel saucepan or box over the power transformer (ground ir a crocodile lead if necessary). You never know, maybe the transformer needs a bit of shielding!

[dpm309]

Matty,

You could also try a phase and ground circuit tester that can be purchased from any Home Depot for about $8.   You will need the 3-prong to 2-prong adapter to use it but it will let you know if your outlets are wired incorrectly.  The one I bought is an orange Sperry Instruments Outlet Circuit & GFI tester.

Dan